Display Pixel Circuit Photodiode Reset Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional display technologies experience uneven brightness due to multiple resets of the photodiode within a scan time per frame, leading to ineffective screen driving and uneven brightness display.
Innovation Solution
The display controller adjusts the input voltage parameters of display pixel circuits based on the location of scan rows within the display area, ensuring different current values for photodiodes when partially or fully within the display area, thereby maintaining a deviation within a preset threshold to prevent uneven brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the photodiode is reset multiple times within a scan time per frame, then the screen contrast is improved, but uneven brightness displaying occurs due to reset operations falling in porch areas
Solution Approach 1:
The patent implements dynamic adjustment of the reset current value based on the real-time position of scan rows. When scan rows are in the display area, one reset current value is applied; when scan rows are in porch areas, a different reset current value is applied. This dynamic adaptation resolves the contradiction by making the reset operation context-dependent, ensuring uniform brightness while maintaining contrast improvement benefits.
Solution Approach 2:
The patent changes the electrical parameter (reset current value) of the photodiode based on the scan row position. By adjusting the reset current value between different operating conditions (display area vs. porch area), the patent achieves both improved screen contrast and uniform brightness display, resolving the technical contradiction through parameter optimization.
2Illumination intensity
If the anode of the photodiode is reset multiple times, then the screen contrast increases, but the reset operation may fall in porch areas where driving is not actually performed
Solution Approach 1:
The patent applies different reset current values for different local conditions (display area versus porch area). By making the reset operation location-specific, the patent ensures that reset operations in porch areas do not waste effective driving time, while still achieving contrast improvement in the display area where driving is actually performed.
3Device complexity
If a fixed reset current value is used for all scan rows, then the control is simple, but brightness uniformity deteriorates when scan rows are in different areas
Solution Approach 1:
The patent transitions from a static fixed reset current value to a dynamic reset current value that adapts to the scan row position. The controller dynamically selects appropriate reset current values based on whether scan rows are in display or porch areas, achieving brightness uniformity without excessive control complexity through systematic dynamic adjustment.
Solution Approach 2:
The patent optimizes the reset current value parameter based on operating conditions. By changing the reset current value from a fixed parameter to a condition-dependent parameter, the patent achieves uniform brightness display while maintaining reasonable control complexity through systematic parameter optimization.
Data Source
Figure 1(a)~2(b)
Figure 3
Figure 4a~4b
AI summary
A display, a display module, and an electronic device are disclosed. The display includes a display pixel circuit and a controller. The display pixel circuit includes a first display pixel circuit and a second display pixel circuit. Within a scan time per frame for the display, when any one of a plurality of current scan rows is located in a non-display area, the controller controls an input voltage parameter of the first display pixel circuit corresponding to a current scan row located in a display area to be a first voltage, where a reset current value of a photodiode in the first display pixel circuit is a first current value; and when the plurality of current scan rows are all located in the display area, the controller controls an input voltage parameter of the second display pixel circuit corresponding to the plurality of current scan rows to be a second voltage, where a reset current value of a photodiode in the second display pixel circuit is a second current value, and a deviation between the second current value and the first current value is less than a preset threshold. According to this application, a problem that uneven brightness displaying occurs on the display can be avoided.